Cranberry diseases and their control

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scientific knowledge, policies, or practices.

E&RMERS' BULLETIN lOSl

UNITED STATES DEPARTMENT OF AGRICULTURE.

Diseases

AND THEIR CONTROL

CRANBERRY DISEASES cause large losses each
year. They are due to fungi and abnormal con-
ditions of growth and treatment.

The principal fungous diseases can be prevented
largely by spraying with Bordeaux mixture.

The large losses due to smothering can be avoided
hy proper methods and conditions of picking, stor-
ing, and handling the fruit.

Berries should be picked dry or dried quickly,
handled carefully, kept in a cool wcll-ventilaled
place, and packed preferably in bushel or half-barrel
boxes.

Contribution from the Bureau of Plant Industry

WM. A. TAYI.OH. Chief
Washington, 1). C. December, 1920

CRANBERRY DISEASES AND THEIR CONTROL.

C. L. Shear,

PollnnJof/tut, Frvit-Difiranv lurcxtigationx, llurcau of Plant Industry.

CONTENTS.

Development of cranberry diseases — 3

Sanitary conditions 4

Resistant varieties -V

Diseases discussed

Early-rot ">

Bitter-rot (anthracnosc) 8

End-rot (blossom end-rot and

stem end-rot) 0

Blotch-rot (rot) 9

llard-rot and tip-Might 10

Red-gall 1 1

Page.

Diseases discussed — Continued.

Hose-bloom (Massachusetts false-

blossom, hypertrophy) 12

Red leaf-spot 13

False-blossom (Wisconsin false-
blossom, phyllody) _.. 14

Black-rot 15

Rust 1 r

Rot and spoilage during storage,

shipping, and marketing 17

Smothering 18

Spraying 10

DEVELOPMENT OF CRANBERRY DISEASES.

THE AMERICAN CRANBERRY 1 hits been in cultivation in
this country for nearly :i century. Some of the present cran-
berry meadows have been bearing fruit for 50 years or more. This
long-continued growth of the same crop on the same land under the
same conditions has favored the development and spread of certain
diseases, some of which at present are unknown or rarely found on
wild cranberries. These diseases are gradually spreading and be-
coming more serious.

Wild cranberry plants under natural conditions do not appear to
be> seriously affected by disease. As is generally the case, however,
when a plant is subjected to cultivation and changed conditions and
planted over extensive areas, the opportunities for the development
and distribution of parasites increase and its diseases become more
serious. At the same time the plants under cultivation appear in
some cases to become weakened and more susceptible to disease.

The American wild cranberry occurs from Newfoundland south-
ward along tbe coast and through the Alleghcnies to North Carolina
and westward along the Great Lakes to Wisconsin and Minnesota.
The commercial production of this fruit is at present restricted to a
few States, the bulk of tbe crop being grown in Massachusetts, New
Jersey, Wisconsin, Oregon, and Washington.

1 Vaocinium macrocarpum.

3

4

Farmers' Bulletin 1081.

The cranberry plant differs greatly from most cultivated plants
in its food and water requirements and also in its method of obtain-
ing certain portions of its food. In common with most of the plants
of the heath family, it requires an acid soil and obtains part of its
nutriment through the aid of a beneficial fungus, known as myco-
rhiza, which lives in the rootlets. There is much yet to be learned in
regard to the best conditions and methods necessary for the produc-
tion of the most vigorous and healthy cranberry plants. A plant,
like an animal, when lacking proper and sufficient food or water
becomes weakened and more susceptible to disease than one that is
properly nurtured and hardy.

Every cranberry bog differs from every other, and in many cases
different parts of the same bog differ in the origin and composition
of the soil and in the character and distribution of the soil water
and plant food. Experience, careful observation, and study must
determine the most satisfactory methods of handling a particular bog
in order to obtain the most vigorous, healthy, and productive vines.

SANITARY CONDITIONS.

Much can be done to prevent the development and spread of
fungous diseases nnd increase the vigor and resistance of the vines
by carefully regulating the water supply of the bog during the grow-
ing season.

Many growers keep the bogs too wet, especially on rich peat bot-
toms. This tends to produce an exeessive growth of vines and favors
the fungous diseases. Regular and judicious pruning should be
practiced wherever the growth of vines is heavy. The primings,
unless used for planting, should be destroyed by fire in order to pre-
vent the spread of the fungi which soon develop on them and furnish
a source of infection for the bog. Rotten fruit discarded in sorting
and screening should be buried or otherwise disposed of, so as to
prevent the spread of disease.

RESISTANT VARIETIES.

Certain varieties of berries are more susceptible to disease than
others. Therefore, in making a new planting varieties which have
l>cen found to be most healthy in the locality should be selected where
practicable.

Little attention has yet been given to the selection nnd breeding
of resistant varieties. In general, the smaller, firmer fruited varieties
are less subject to rot than those bearing larger berries.

The average annual cranberry crop of the United States is about
500,000 barrels, valued at $3,000,000. The total loss from disease

Cranberry Diseases and Their Control.

5

is estimated to average at least 25 per cent, or $750,000 a year. Of
this loss about 10 per cent occurs before the fruit is picked and 15
per cent after picking. The losses seem to be greater in the southern
localities. The longer summers and higher average temperatures in
the South are apparently less favorable to the production of hardy
cranberry plants, while they seem more favorable to the development
of certain serious fungous parasites.

DISEASES DISCUSSED.

The following diseases will be discussed here. They are arranged
in the order of their destructiveness, the worst being presented first.
Several others are known, but they are regarded as of no great eco-
nomic importance at present.

Early-rot . (scald, blast,
dead-spot, leaf-spot).

Bitter-rot (antlmicnose).

Knrt-rot (blossom end-
rot, stem end-rot).

151otcli-rot (rot).

Hard-rot.

Tip-blight.

Red-gall.

.Rose-bloom (Massachusetts

false-blossom, hypertrophy) .
Red leaf-spot.
False-blossom (Wisconsin

fa 1 se-bl ossi >m , phy 11 ody ) .
Black-rot.
Rust.

EARLY-ROT.

The name early-rot is applied to the disease caused by a fungus 1
closely related to that producing black-rot of the grape. The differ-
ent stages and forms of reproduction of this parasite are shown in
figure 1. The fungus attacks all of the aerial portions of the plant.

The most serious injury is usually caused by the destruction of the
fruit, which may be attacked at any time during its development.
Under favorable conditions for the growth and distribution of the
fungus it attacks the flowers and very young fruits, causing the
latter to shrivel and become blackened and finally covered with the
spore-bearing pustules of the parasite. This form of the disease has
sometimes been called blast and sometimes blight. Blossoms and
young fruit frequently fail to develop from other causes, such as
imperfect fertilization of the flowers, or from unfavorable weather
conditions, such as excessive heat or cold or excessive moisture or
drought, or from insects or fungous diseases. Wherever the injury
is due to early-rot it is followed by the development of the minute
black fruiting bodies of the fungus on the blackened and more or less
shriveled young fruit of the cranberry.

The fruit attacked by this disease when half grown or more shows
at first a minute light-colored soft spot on the surface. This spot

1 Guignartlia vaccina Shear.

6

Farmers' Bulletin 1081.

spreads in a concentric manner until finally the whole berry becomes
soft and sometimes marked by more or less distinct dark-colored
rings. If the rot develops rapidly, however, the berry may show little
discoloration. Occasionally the rot is restricted to a small area on
the fruit and the tissues become sunken, and sometimes the minute-
black spore-bearing bodies of the parasite develop. Ordinarily, how-
ever, there is no indication on the surface of the fruit of the presence
of the parasite except the occasional dark spots or brownish zones.

Berries attacked before they
are three-fourths grown fre-
quently shrivel or become
mummied and blackened and
covered with the fruiting
bodies of the fungus. This
condition is more frequent in
New Jersey than in more
northern localities, where the
disease does not usually make
its appearance until the fruit
is nearly half grown.

The disease as it affects the
nearly grown fruit was for-
merly called scald, especially
in New Jersey. This name
had its origin in the belief
previously held by many
growers that the softening of
the fruit caused by the fungus
was due to the action of the
hot sunshine upon the berries
when wet with dew or rain.
Occasionally a real scalding
occurs on berries which have
been overflowed and covered
with water for half a day or
more during hot weather.
Injury of this kind, however,
is infrequent and can be dis-
tinguished from that caused by fungi by the difference in effect upon
the tissues of the fruit. In the case of fungous injury the tissues
beneath the skin are mostly destroyed, but the berries remain turgid
and elastic under slight pressure. In the ease of sun scald, the tissues
beneath the light-colored spot are more or less collapsed, or shrunken.,
or withered, and the spot does not increase in size, as in the ease of
early-rot.

Fio. 1. — The early-rot fungus : a, b, and o,
Fruiting bodies on loaf, stem, and fruit (nat-
ural size) ; d and e, pycnldlum and sporea ;
f, g, and h, perlthecium and ascospores (much
magnified).

Cranberry Diseases and Their Control.

7

Occasionally this fungus also attacks the foliage of the plant,
causing an irregular reddish hrown spot, which may show spore-
bearing pustules (pycnidia or perithccia) of the fungus. Usually,
however, where the fungus invades the whole leaf it produces no
spot, but causes the leaf to drop prematurely. The fruiting pus-
tules of the fungus develop chiefly on the leaves after they have
fallen. Tf cuttings from bogs affected with this disease are planted,
the young growth is frequently defoliated by this fungus and some-
times is so seriously injured that the plants die. In old plantings
the disease, when very severe, sometimes causes the death of the
plants in spots. These are sometimes called dead spots and also, in-
correctly, ringworm. The latter name should not be used in con-
nection with fungous diseases, as there is an insect which produces
similar dead spots. Where the vines are killed there is no evidence
to be found of any injury to the root system by insects or other
agencies and the dead foliage of the plants is covered with the
fruiting pustules of the early-rot fungus. Sometimes other fungi
are also associated with this, tending to increase the injury.

Early-rot is found in all the cranberry -growing sections of the >
country and is widely distributed on the native wild cranberry plants.
It is most prevalent and produces most injury in the southern areas
of cranberry cultivation. In the northern areas it appeal's later in
the season and sometimes does not develop until after the fruit haS
been harvested. Much loss from this disease is caused as a result
of dormant infections, which develop and destroy the berries during
the period of sorting, packing, shipping, and marketing.

CONTROL.

Experiments conducted by the United States Department of Agri-
culture and also the experience of various growers during the last
10 years have demonstrated that this disease can be satisfactorily
prevented by thorough spraying Avith 3-3-50 soap-Bordeaux mix-
ture. This mixture should be prepared as follows:

Ctopper sulphate (blue vitrol or Milestone) pounds.. ' 3

Fresh stone lime do 3

WiUwr gallons^ HO

Commercial resln-flsholl soap pounds — 1

The soap should be dissolved in about 10 gallons of water and
added after the lime and blucstonc have been mixed. The two
requisites for the production of good Bordeaux mixture are fresh
stone lime and the thorough mixing of the liinc and blucstone
solutions. The soap has been found necessary in order to cause the
mixture to spread and adhere to the glossy surface of the cranberry
fruit and foliage. Where early-rot is serious, at least four applica-

8

Farmers' Bulletin 1081.

tions of Bordeaux mixture should be made during the season, using
150 to 200 gallons to the, acre. The first application should be made

just before the flowers begin to open,
the second when the blossoms begin to
fall, the third two weeks later, and in
severe cases a fourth not later than
August 15, as later applications are
likely to produce a staining of the fruit
which may not be washed off before
picking.

BITTER-ROT 1 (ANTHRACNOSE).

This disease is very similar to the bitter-
rot of apples and other fruits. The
different spore forms and the fructifi-
cations of the fungus are shown in figure
2. This fungus attacks both the foliage
and the fruit, causing most injury, how-
ever, to the fruit. The appearance of
bitter-rot on the fruit is not easy to
distinguish from several other rots
which attack cranberries, and unless the
fungus happens to be fruiting on the
berries it is usually impossible to deter-
mine positively the cause of the rot with-
out making cultures from the tissues of
the affected berries or making a careful
microscopic examination of the fungus
in the interior of the fruit. Affected
berries become softened and show more
or less of a brownish yellow discoloration.

Bitter-rot is widely distributed and
has been found in New Jersey, New
York, Massachusetts, AVisconsin, Wash-
ington, and Oregon. Its seriousness in
any particular locality appears to be
closely associated with the weather con-
ditions. Hot weather during July and
August appears to be most favorable for
its development. The disease usually
season, and frequently not until after the

Pro. 2.— Tlio bitter-rot fungus:
a, h, and c, Conidial fructifi-
cations ; (I, e, and f, porithe-
clum and ascospores. (All
much tnagnillod. )

develops rather late in the
fruit has been harvested.

1 Caused by QlomereUa clngulata vaceinii Shear.

Cranberry Diseases and Their Control.

9

CONTROL.

Bitter-rot is somewhat more difficnlt to control than early-rot.
The treatment should be the same as for early-rot, using Bordeaux
mixture as recommended and making four applications. Special
effort should be made to get the mixture on the vines before a rain.
If this can not be done, it should be applied immediately afterwards.

END-ROT 1 (BLOSSOM END-ROT AND STEM END-ROT).

End-rot is a fungous rot of cranberries which has been distin-
guished from the other rots only within the last few years. It has
been found, however, in all the cranberry-growing districts of the
United States and has been the cause of considerable loss recently in
Massachusetts and Wisconsin. It is called end-rot because, so far as
known at present, it always starts at cither the blossom or stem end
of the berry. Most of the other rots usually start at some other point
on the fruit. Aside from the fact that this rot usually begins at the
end of the berry, it has no characteristic which makes it distinguish-
able from some of the other cranberry rots. The fruit when attacked
becomes softened and the skin light colored or yellowish. The trouble
develops late in the season, especially after picking and packing,
and is most common in the northern sections.

CONTROL.

Experiments conducted during the last few years in cooperation
with the Massachusetts Cranberry Experiment Station at East Ware-
ham, Mass., have shown that end-rot is reduced by spraying with
Bordeaux mixture, as recommended in the regular treatment for
early-rot.

BLOTCH-ROT * (ROT).

As in the case of some of the other fungous rots of the cranberry,
the appearance of the fruit attacked by blotch-rot is not sufficiently
distinct for the grower to distinguish it from some of the other rots.
The disease is due to the fungus which is shown in the accompany-
ing illustration (fig. 3). This rot first appears as a small, light-
colored, soft spot on the berry, finally spreading and destroying the
whole fruit. In the later stages of its development it very fre-
quently, though not always, produces small dark-colored blotches in
the skin of the fruit. This appearance has suggested the proposed
common name, blotch-rot. The only way in which this disease can
be positively determined, however, is by making artificial cultures of

1 Caused by Fufticoccum putrefaeien.fi Shear.
s Caused by Acanthorynchus vaccinii Shear.

10

Farmers' Bulletin 1081.

the fungus from the diseased berries, a method only available to the
plant pathologist. This fungus also attacks the leaves, but it is

very rarely found fruiting on them
until after they have fallen to the
ground.

Blotch - rot has been found
throughout the cranberry - growing
sections of the United States and
also Nova Scotia. Just how much of
the annual loss from rot is due to
this disease it is impossible to say, on
account of the difficulty of distin-
guishing it from other diseases.
The fungus occurs so frequently,
however, in cultures from diseased
berries that it is probably one of the
connnou causes of rot.

CONTROL.

Spraying with Bordeaux mixture,
as recommended for early-rot, is
a satisfactory preventive of this
disease.

HARD-ROT AND TIP-BLIGHT. 1

Hard-rot and tip-blight are forms
of a fungous disease caused by an
organism closely related to the
brown-rot fungus which attacks
peaches and other fruits. The first
appearance of this disease is to be
found on the young growing tips of
the plants just before blossoming.
The affected tips wilt and dry up,
and the gray or white conidia of the
fungus develop on them. This is the
tip-blight form of the disease.

Later in the season the fungus at-
tacks the fruit, apparently gaining
entrance through the blossoms and
Fruiting bodies; o and a, organs of producing what is termed "hard-

ZTZt'lzllir ftnd 8P ° reS - ™t" The appearance and character

of the fruit affected with this dis-
ease, are well marked and easily recognized when once seen. The

Fig. 3. — Tbe blotch-rot fungus : a And l>.

1 Caused by BcleroUnla oxycocci Wor.

Cranberry Diseases and Tlieir Control.

11

affected berries instead of coloring up naturally as they approach
maturity become a more or less sordid, pale, yellowish white color,
and instead of becoming softened, as in the case of most other fungous
diseases, the tissues remain rather firm and leathery. Upon cutting
an affected berry through the center the seed cavities will be found
to contain a white fungous growth having a cottony appearance.
Later in the season such berries shrivel, become darker and harder,
and finally become mummied. These mummies contain the sclerotia
or resting form of the fungus, which lives over winter. The mature
or asens-bearing form of the fungus has not yet been found on the
cranberry, but should be produced from these mummies during the
following spring or early summer.

Hard-rot and tip-blight thus far have been found only in Wisconsin
and on the Pacific coast. Fortunately, the disease has not yet been
very serious. If it should become general it has possibilities of caus-
ing much loss, as the affected tips die and bear no fruit and the
affected berries are worthless.

CONTROL.

The uncertainty of the occurrence of hard-rot and its scattered
appearance have prevented the careful testing of fungicides. From
our knowledge of diseases caused by closely related fungi, such as
the brown-rot of peaches, plums, etc., there

is reason to believe that this disease can be Ji a Jft

prevented by spraying witli Bordeaux *" = j5fc^' /nU |L-
mixture. The first application, however, /,\W J&iAk^^M
should be made as soon as the new growth Jf« 'SfrTOs&^ervyy
starts, in order to prevent the infection of * '* '■>■'■"
the tips. Further applications should be ^tffjb/j #
made as for early-rot. Si c

RED-GALL. 1

Fia. 4.- — The red-gall fungus,
showing (u) leaves and
flower bud affected with

The red-gall of cranberries is a disease gaiis (natural size), (6) <>n-
which once seen is very easily recognized. '" rsCfl | S,,1S,(> snl1 ' ( f> s *=-

, ' , ,. , Won through a single gall

ihe galls are caused by the lnngus shown (much magnified), showing
in figure 4. The disease usually appears tho f,,nsns ln a cU-cn, " r mass

. , , ?U ln tni ' "'nter.

just before Ihe blossoms open. The buds,

young leaves, and shoots become more or less covered with small,
red, somewhat irregular globular galls about the size of bird shot.
The affected shoots produce no fruit.

Red-gall is very erratic in its occurrence. The cases thus far
observed have appeared on a large number of plants on certain bogs
during a particular season and have frequently disappeared the next
season. The distribution and developmenl of the parasite seem to

1 Caused by Synelvyirium mrcinU Thomas.

12

Farmers' Bulletin 1081.

depend primarily upon the water conditions of the hog and the
amount and distribution of the rainfall. The spores of the fungus
are adapted to distribution by water. The affected bogs are usually
those which have an excessive water supply or which are uneven and
not properly drained. This disease has been found thus far only in
eastern cranberry bogs and most frequently in New Jersey.

CONTROL.

The proper grading of the bog and the control of the water sup-
ply seein to be the best methods of preventing red-gall. Its uneer-

t'la. 5. — Cranburry rose-bloom, showing' tlia abnormal, flowerlike, enlarged lateral

shoots.

tain occurrence and the impossibility of ascertaining its presence"
until the young galls appear render it impracticable to employ spray-
ing as a means of prevention. Bogs which are properly drained and
from which the flood waters are removed early are rarely, if ever,
seriously affected with this disease.

ROSE-BLOOM 1 (MASSACHUSETTS FALSE-BLOSSOM, HYPERTROPHY).

l?ose-bloom was first observed in Massachusetts and has since been
found in the States of Washington and Oregon. It does not appear

J Caused by K-TobaKiiUum oi-ycocct Host.

Cranberry Diseases and Their Control. 13

to bo widely distributed at present and has proved a serious cause
of loss on only a few bogs. Like the red-gall it is rather erratic
in its appearance, occurring in abundance one season and perhaps
being of little importance on the same bog the next season. It has
been found most serious on the Matthews variety in Massachusetts.
The disease first makes its appearance on winter-flowed bogs soon
after the water has-been removed in the spring. The buds in the
axils of the leaves of the fruiting shoots, which usually remain
dormant, are attacked by the fungus, which stimulates growth, re-
sulting in abnormal lateral shoots bearing enlarged, swollen pink
or light rose-colored distorted leaves. The appearance of these
shoots is shown in the accompanying illustration (fig. 5). These
colored hypertrophied leaves being somewhat crowded together bear
a slight superficial resemblance to a flower. This has led to the use
of the common names, •rose-bloom and false-blossom. The term
"false-blossom," however, should be restricted to another disease,
to be described later, to which it is more applicable. As this disease
usually develops before the blossoms appear, the vitality of the
shoot is exhausted and no fruit is produced. Vegetative shoots,
or runners, are sometimes attacked also. In such cases, of course. the
injury is of less importance. The occurrence of rosc-bloom is usually
associated with an excessive water supply, which seems to favor its
development. Holding the winter flowage until late and reflowing
tend to increase the disease when present.

CONTROL.

Early spraying with Bordeaux mixture appears to be helpful in
controlling rose-bloom. When the disease is known to occur on a
bog the water should bo removed earlier in the spring than -usual
and reflowing avoided if practicable.

RED LEAF-SPOT. 1

Red leaf-spot is caused by a fungus very closely related to the one
producing rose-bloom; in fact, some investigators regard them as
merely "forms of the same species. The effect upon the plant, how-
ever, is quite different. The red leaf-spot, as shown in the accom-
panying illustration (fig. G), produces a more or less circular spot
upon the leaf and is usually bright red, especially on the upper side.
On the lower side the spot is paler and covered with fine spore-bear-
ing filaments of tlie fungus, giving the appearance of a dense bloom
or powder.

This disease has been found in all cranberry-growing sections,
but it does not usually cause serious injury to the plants except in

r Cnxiso<] by Exnhattitliitm ruccinii (Fckl.) Wor.

14

Farmers' Bulletin 1081.

"Washington and Oregon, where the climatic conditions, especially
damp weather, and the luxuriance of growth of the vines appear to
furnish unusually favorable conditions for the development and
spread of the fungus. That an excess of moisture in tho form of
fog, rain, or flood is the principal factor in making this a serious
disease is indicated by the behavior of this fungus in Massachusetts
in 1916. The greater part of that, season was unusually wet, and red
leaf-spot was much more common than usual. Though the fungi
producing rose-bloom and red leaf-spot are so very closely related,
tho two diseases have been rarely found to occur together. Occa-
sionally they may be found
on the same bog, but rarely
or never on the same plant.

CONTROL.

Spraying with Bordeaux
mixture, as for early-rot, ap-
pears to be effective in eon-
trolling red leaf-spot, accord-
ing to the experience of some
Pacifie-coa'sl growers.

FALSE-BLOSSOM (WISCONSIN
FALSE-BLOSSOM, PHYL- ,
LODY).

The real cause of the dis-
ease known as false-blossom
is at present unknown.
Studies thus far have failed
to show that it is due either
to insects or to fungi. It is
also uncertain whether it is
of an infectious nature. Some
observations seem to indicate
that the trouble may be caused, in part at least, by unbalanced nutri-
tive conditions. False-blossom lias been found chiefly in "Wisconsin.
The cases which have been found in Massachusetts, New Jersey,
Washington, and Oregon appear to have originated, in most instances
at least, from plants obtained from "Wisconsin.

The chief features of this disease are shown in the accompanying
illustrations (figs. 7 and 8). In its simplest form the flower pedicels
become more or less erect instead of drooping, the calyx lobes become
enlarged and somewhat loaflike, and the petals are short and broad
and slightly reddish or greenish in color. The stamens and pistils
arc more or less aborted and malformed, and affected plants pro-

V\c. (>.- -IUmI leaf-spot of tho cranberry.

Cranberry Diseases and Their Control.

15

duce little or no fruit. All intermediate forms and gradations can be
found among diseased plants, from the simplest stage, in which there
is only a shortening and thickening of the parts of the flower, to cases
in which the entire flower is replaced by- a short branch with small
leaves, as shown in figure 8, d and e. Affected plants also show a
marked tendency toward the development of abnormal terminal buds
and of lateral branches arising from the usually latent axillary buds.
Such branches are slender and weak
and fail to produce normal flowers or
fruit. They give the plant a kind of
witches'-broom appearance, as shown in
figure 7.

This trouble is usually associated
with extreme wet or dry conditions of
the bog, but most frequently with an
excessive water supply. In most of the
localities in which it has been observed
the affected plants were growing in a
deep, coarse peat soil having an exces-
sive water supply during the greater
part of the growing season.

CONTROL.

In the absence of more definite knowl-
edge of the exact cause of false-blossom
it is impossible to recommend satisfac-
tory methods of prevention and control.
The best conditions possible for normal
growth should bo provided, especially
good drainage, clean culture, and prun-
ing. "Where a large number of the
plants in a bog are affected with false-
blossom it would probably be best to
remove and burn the diseased plants
and to replant with healthy vines. To
prevent the further introduction and
spread of the disease only vines known to be absolutely free from
false-blossom or coming from localities free from the disease should
be used in planting.

BLACK-ROT. 1

Fig. 7. — False-blossom of the cran-
berry, showing tho wttchos'-broora
form duo to tho abnormal develop-
ment of axillary buds.

Black-rot develops chiefly in fruit after picking. The affected
berries become very dark colored and softened. The fungus causing

1 Caused by Ccutliospora hinata Shear.

16

Far mem' Bulletin 1081.

Fig. 8. — False-blossom of the cranberry, showing various abnormal developments of the
flowers : a and b, Floral parts changed to greenish leaflike bodies ; c, d, and "e, floral
parts changed to leafy shoots.

Cranberry Diseases and Their Control.

17

this disease has also been found on dead and dying leaves, bnt has
not caused much injury. It has been found most frequently on fruit
from Massachusetts and New Jersey.

CONTROL.

Bogs which have been thoroughly sprayed usually show little of
this trouble, and its development can be largely prevented by proper
conditions of storage and handling of fruit, as mentioned on page 18.

RUST. 1

This disease has thus far been observed only in the cranberry bogs
on the Pacific coast and has caused no serious injury ; but if it should
develop in an epidemic form, as is possible, it might do consider-
able harm to cranberries. It- is caused by one of the rust fungi,
which forms minute yellowish powdery pustules on the under side
of the leaves.

The early spore stage of this fungus develops on hemlocks, and
on the Pacific coast will probably be found upon the western hem-
lock. The disease is likely to occur, therefore, in the East or the West,
wherever hemlock is found near cranberry bogs.

CONTROL.

Tf the rust should prove sufficiently serious to justify the expense,
it could probably be controlled by the removal of the hemlocks in
the vicinity of the cranberry bogs, if this should seem practicable.

ROT AND SPOILAGE DURING STORAGE, SHIPPING, AND

MARKETING.

Until recently the losses from fungous diseases which occur after
the crop is harvested have been more or less overlooked and neglected.
In the ease of the cranberry, the losses after picking are frequently
much more serious than those occurring before harvest. These
losses are due chiefly to two causes: Fungous parasites which have
infected the fruit before picking but have remained in a dormant
condition and the smothering or killing of the fruit by lack of
ventilation.

By observation and investigation it has been found that abont
one-half of the loss of berries after picking is due to fiingi. The
most frequent and important of these fungous rots in recent years
have been the early-rot and the end-rot. The development of these
rots after picking depends largely upon the conditions under which
the -fruit is kept and the methods of handling. Where experience

1 Caused by Pucciniantrum myrtllll (Sebum.) Artb.

18

Farmers' Bulletin 1081.

hits shown that serious losses occur after picking, spraying should
be practiced, as recommended for the control of these rots, as this
will prevent largely the infection of the fruit which occurs before
picking and thus greatly reduce the losses which develop after
picking.

The fruit should be picked dry or dried very quickly after picking,
as cranberries which are stored when wet rot more quickly than dry
fruit. Great cure should ho used in handling the fruit. Even
slight bruises greatly increase the amount of rot. The berries should
be run through the separator only once. In sorting or screening,
squeezing the berries should be avoided, and in running berries into
barrels or boxes some sort of easer should be used to break the fall
and prevent bruising.

The temperature under which the fruit is kept is a very important
factor in determining its keeping quality. High temperatures greatly
favor the developmenf of fungous rots. As the fruit is usually
warm when picked it should be placed in the shade and cooled
as rapidly as possible. The storehouse should be well ventilated at
night and closed as far as possible during the day, when the outside
temperature is usually higher than that inside. In sorting or screen-
ing the fruit in cold weather the berries should be kept in a warm
room as short a time as possible and packed in a cool room.

SMOTHERING.

Besides the fungous rots, a largo amount of spoilage of stored
fruit is due to the premature death of the berries and the physical
and chemical changes which follow. Such fruit becomes somewhat
softened throughout, discolored, and practically worthless. Upon
cutting open such berries it will be found that the interior is red
and juicy and its natural flavor gone. The cranberry, when picked,
is a living organism, carrying on active life processes which are
continued under ordinary conditions for a considerable time after
the fruit has been removed from the vines. In order to keep the
fruit it is necessary to prolong as far as possible these life processes
and prevent death. The cranberry may be said to breathe in its
own peculiar way, and when it is prevented from so doing it suffo-
cates and dies. The more rapid this breathing the more quickly is
the fruit spoiled.

Tn general, it has been found that high temperatures hasten the
death of the fruit by smothering. High temperatures and lack of ven-
tilation are the chief causes of smothering. In order to reduce such
loss to a minimum the fruit should be cooled as quickly as possible
after picking, being set in a shady well-ventilated place either under
trees or under a simple roof of boards or canvas. The berries should

Cranberry Diseases and Their Control.

19

never be covered tightly by spreading canvas or oilcloth over piles of
boxes unless the weather is cold.

As much as possible of the hauling to the storehouse should be
done early in the day, and the house should be so arranged as to
cool the fruit quickly and keep it cool. Ventilating should be done
at night and the storehouse kept closed as much as possible during
the day. In packing cranberries for market ventilated containers are
preferable, especially during warm weather. Half-barrel or bushel
ventilated boxes have been found more satisfactory than barrels in
reducing the losses from rot and smothering during shipping and
marketing.

Via. 9. — A gasoline-engine spraying outfit on two trucks.

SPRAYING.

The conditions under which cranberries are grown and the char-
acter of the plants are so different from those which obtain with other
fruits that special methods have been found necessary for the most
economic and effective application of fungicides and insecticides.

On the small areas sometimes found in Massachusetts knapsack
sprayers may be sufficient, and on small bogs with a sufficiently firm
bottom a barrel and eart outfit can be used. Tt is not often practicable
to use a team on a bog, not only on account of the very soft bottom
hut especially because of the injury to vines and fruit. As it is not

Farmers' Bulletin 1081.

feasible to haul a "heavy power sprayer over the bog, some other
arrangement must be made.

The most generally satisfactory outfit yet devised for the rapid,
effective, and economical spraying of extensive areas of bog is a large,
gasoline engine sprayer with stock-supply tanks mounted on a sepa-
rate truck, which may be moved to convenient points on the margins
of the bog or dams, where water may be pumped directly from the
stream or ditch into the mixing tanks. Where the bog is not too
large it may be sprayed by hose direct from the pump, moving the
outfit about the margin of the bog or dams when necessary. The

Via. 10. — Device for limiting Kordamix mixture. Pulverized bluestone Is being dissolved
in one compartment and iime in the other, the two solutions running together in
the trough below.

spray mixture may then be distributed to various parts of the bog
through galvanized-iron pipes arranged about the margin of the bog
and across it in such manner that by means of long leads of hose con-
nected at different points all parts of the bog may bo reached.

The capacity of the engine, pumps, and tanks will depend upon
the area to be sprayed and the number of spray nozzles which can be
most effectively used. The following description and illustrations
of an outfit used on a large bog in New Jersey will indicate the essen-
tial features. Those planning to install a spraying system for cran-
berries should inspect and study some satisfactory outfit already in

Cranberry Diseases and Their Control.

21

operation in order to learn all the essential details and decide just
what is necessary to adapt the system to their particular conditions.

The outfit referred to, with two trucks, engine, pumps, and tanks,
is shown in figure 9. A 9-horsepower gasoline engine and a 3-cyliu-
der high-pressure pump are used ; also a centrifugal pump to fill the
tanks. On the rear truck are two 200-gallon tanks and a mixing
outfit. The arrangement for dissolving and mixing the bluestone
and lime is shown in figure 10. A quantity of pulverized bluestone
sufficient for a tank of spray mixture is placed in one of the vessels,
and the necessary quantity of slaked or hydrated lime in the other.
These materials are dissolved by pumping water through the hose
inserted in the top of each container. The dissolved materials come
out of the lateral spouts at the bottom of the vessels and are mixed
as they fall into a trough, in the sides of which blocks are inserted

Fig. 11. — A gang of five cranberry sprayers each with a 4-nozzlc spray rod.

to cause the more thorough mixing of the two solutions as they run
into the spray tank. To provide a continuous supply of spray mix-
ture one tank is being filled while the other is being used. The
pumps are connected with hose with galvanized-iron piping, 1 inch
or 1\ inches in diameter, depending upon the length required to
reach around the bog. This pipe is placed on posts about a foot
high, to prevent rusting, and extends about the margin of the bog
and the dams also if necessary.

» In the illustration on the title-page the connection of the spray
hose to the pipe lino is shown ; also a hose cart for moving the long
leads of hose from one connection to another on the pipe line and for
lengthening or shortening the hose according to the needs of the
sprayers.

The spray mixture is distributed by a galvanized-iron spray rod
with four or five nozzles attached at intervals near one end, as shown

22

Farmers' Bulletin 1081.

in figure 11. Hie spray hose is curried from the reel across the bog
on a series of short posts with rollers at the top, as shown in the
right-hand margin of the illustration.

Two hose reels and two gangs of nine men are used with this out-
fit. The two gangs under favorable conditions can cover 8 acres
an hour, using about 200 gallons of spray material to the acre. The

under side.

usual maximum area sprayed is GO acres a day, as some unavoidable
interruptions of the work are likely to occur. This general plan can
be adapted to any large bog.

Another style of spray rod, shown in figure 12, is used by some
growers. This consists of a galvanized-iron pipe with a number of
nozzles attached at regular intervals on the under side and carried
by two men. Tliis is very satisfactory for medium-sized bogs and
fewer men.

WASHINGTON : fiQVERNMKXT 1'HINTINr, OFFICIO : 1820